At present, e.g. in trade shows, when two people meet and one of them desires to receive additional information from the other, and vice versa, such as a CV, a business brochure, product documentation, audio or video demonstration files, or any other information that is not immediately available, they exchange respective business cards that give their contact details, in particular e-mail addresses, and they specify orally or in writing, the additional data that they desire to receive from each other. On getting back to their desks or homes, after the show is over, these people can then send the requested items to the other parties by mail, fax, or e-mail providing the items in question are available in the form of digital data. In a variant, each person may go and retrieve the data from an Internet site whose URL address has been provided by the other party, possibly together with a confidential access code.
That process of supplying information, which operates essentially in deferred time, is restrictive and ill-suited to making multiple contacts where a very large amount of data needs to be exchanged between a large number of parties.
Thus, a few years ago, there appeared what can be referred to as a “CD-ROM business card” which is in the form of a computer-readable digital compact disk with the dimensions of a credit card. Thus, on meeting another party, digital data of one or more of the kinds defined above can be transferred immediately. Nevertheless, the storage capacity of such cards is restricted, and once the CD has been written, it can no longer be changed. The information provided is thus frozen at its date of manufacture and cannot be updated subsequently. In addition, the cost of producing such CD-ROM cards is still relatively high.
More recently, portable computer devices known as personal digital assistants (PDAs) have appeared on the market that enable digital data to be exchanged with an external computer or another PDA over an infrared link or a radio link. Nevertheless, in this case also, the volume of information that can be transmitted is limited by the memory capacity of such devices (it is difficult to exchange video files, for example), and in addition transmission between two such devices requires them to be fully compatible and requires a specific data exchange protocol to be complied with (and if the link is an infrared link, the two devices need to be carefully positioned relative to each other).